Kepler Laws
Kepler Laws
Kepler’s Laws of Planetary Motion:
Johannes Kepler proposed three laws of planetary motion in 16th century. The three laws are given as below:
1. Kepler’s First Law:
It states that the path of any planet in an orbit around the sun follows the shape of an ellipse with the sun at one of its foci. The point in the orbit of a planet nearest to the sun is called perihelion and the point farthest from the sun is called aphelion.
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2. Kepler’s Second Law:
It states that an imaginary line from the sun to the planet sweeps out equal areas in equal intervals of time. Thus, if the time of travelling of a planet from P1 to P2 and from P3 to P4 is same, then the areas Area1 and Area 2 are equal.
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3. Kepler’s Third Law:
It states that the cube of the mean distance of a planet from the sun is directly proportional to the square of its orbital period T. It is expressed as
where T = time period of the planet (around the sun), r = radius as mean distance of the planet from the sun and K = Kepler constant. Kepler could not give a theory to explain the motion of planets. Newton showed that the cause of the planetary motion is the gravitational force that the sun exerts on them. Newton used Kepler’s third law to calculate the gravitational force of attraction. Suppose the orbital velocity is v and the radius of the orbit is r. Then, the force acting on an orbiting planet is given by
where, m is the mass of planet.
If ‘T’ denotes the time period, then
Substituting the value of v in Equation 1, we get
But according to Kepler’s third law of planetary motion,
Putting this value into equations, we get
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Kepler’s Second Law states that an imaginary line from the sun to the planet sweeps out equal areas in _______________ intervals of time. | |||
| Right Option : B | |||
| View Explanation | |||
Which of the following are correct : (a) The point in the orbit of a planet nearest to the sun is called perihelion. (b) The farthest point in the orbit of a planet from the sun is called perihelion. (c) Kepler’s Second Law states that an imaginary line from the sun to the planet sweeps out equal areas in equal intervals of time. | |||
| Right Option : C | |||
| View Explanation | |||
The point in the orbit of a planet nearest to the sun is called ________________________. | |||
| Right Option : A | |||
| View Explanation | |||
Students / Parents Reviews [10]
My experience with Abhyas is very good. I have learnt many things here like vedic maths and reasoning also. Teachers here first take our doubts and then there are assignments to verify our weak points.
Shivam Rana
7thAbhyas is a complete education Institute. Here extreme care is taken by teacher with the help of regular exam. Extra classes also conducted by the institute, if the student is weak.
Om Umang
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Ayan Ghosh
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Archit Segal
7thAbout Abhyas metholodology the teachers are very nice and hardworking toward students.The Centre Head Mrs Anu Sethi is also a brilliant teacher.Abhyas has taught me how to overcome problems and has always taken my doubts and suppoeted me.
Shreya Shrivastava
8thIt was good as the experience because as we had come here we had been improved in a such envirnment created here.Extra is taught which is beneficial for future.
Eshan Arora
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Yatharthi Sharma
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Barkha Arora
10thIt was a good experience with Abhyas Academy. I even faced problems in starting but slowly and steadily overcomed. Especially reasoning classes helped me a lot.
Cheshta
10thOne of the best institutes to develope a child interest in studies.Provides SST and English knowledge also unlike other institutes. Teachers are co operative and friendly online tests andPPT develope practical knowledge also.
